A high level of cholesterol in the blood is a risk factor for cardiovascular disease. Different studies have demonstrated that people who consume diets rich in fiber have lower amounts of cholesterol and LDL in the blood than people who consume less fiber (cf. M. H. Davidson et al., “Effect of hydroxypropylmethylcellulose on serum lipids in subjects with mild-to-moderate primary hypercholesterolemia”, J. Am Col Card, 1998, vol. 31(2) Suppl. A:319A). The beneficial effects of fiber are also known for protecting intestinal barrier integrity and preventing colon cancer.
Nevertheless, nowadays, the therapeutic application of dietary fiber supplements available in the market is very problematic, mainly due to the fact that these natural fibers are mixtures of substances with a highly variable and heterogeneous chemical composition, with the only common property that they are components of food that are not attacked by human digestive enzymes. Therefore, it is difficult to define the active ingredients in such supplements and to quantify the dosages.
Dietary fibers contain some pharmacologically active compounds, but they mainly contain products with little or no activity, such as celluloses or hemicelluloses. Minority components of the dietary fiber are polyphenols. The term polyphenol covers a large number of secondary metabolites of vegetables, which are structurally characterized by having aromatic rings with hydroxyl groups. In plants, polyphenols can be found free or associated to components of the cellular wall. This localization, together with their molecular weight, allows for differentiation between soluble and insoluble polyphenols. Insoluble polyphenols have a greater molecular weight and have the beneficial health effects indicated above.
Nevertheless, insoluble polyphenolic compounds are present in small amounts in fiber of the most commonly consumed vegetables or in commercial dietary supplements of fiber. Moreover, most of these insoluble polyphenols are not usable in their natural state in the necessary doses for chronic treatment of degenerative diseases, because they have a strong astringent and anti-nutritional effects due to the inhibition activity of the digestive enzymes, which form complexes with proteins.
One of the dietary fibers with higher polyphenol content is carob bean fiber, from the fruit of the carob tree (Ceratonia Siliqua). One commercial fiber with a high polyphenol content is called “carob fiber”, of C.G.A. S.A. (cf. ES 2,060,543). Another carob bean fiber is described in the patent document ES 2,204,301. Both fibers have a polyphenol content of approximately 50% of the dry weight. These fibers reduce cholesterol levels in rats, but extrapolation to a human scale of the doses used in studies with animals would require amounts between 25 and 50 g/day, which are very high doses for therapeutic use.
Attempts have been made to increase the insoluble polyphenol content in dietary fiber. One example is a carob bean fiber containing nearly 90% of insoluble polyphenols that have been thermally modified in order to eliminate their astringent and anti-nutritional effects (cf. ES 2.187.356).